Field
The present disclosure relates to an information processing apparatus, an information processing method, and a storage medium.
Description of the Related Art
There is a technique relating to mixed reality in which information of a virtual space is superimposed onto a real space and provided to a user. In the mixed reality, a combined image is displayed by superimposing an image (i.e., computer graphics (CG)) of a virtual space onto all or a part of a real video image captured by an imaging apparatus such as a video camera according to a position or an orientation of the imaging apparatus.
By extracting a region such as a user's hand from a video image of a real space, it is possible to determine whether interference occurs between the region of the real space and a CG, or to determine the anteroposterior relationship between the relevant region of the real space and a CG. In the description below, a region of an object such as a user's hand in a captured image is referred to as an object region as necessary.
The object region is extracted through various methods such as a method which executes region division, a method which dynamically extracts a contour, and a method which uses a learning result. In any of the above methods, an initial object region is detected by extracting a color of the object region (e.g., a flesh color). The above technique for extracting the color of the object region is described in Japanese Patent Application Laid-Open No. 2007-257087, Japanese Patent Application Laid-Open No. 2005-228140, or Japanese Patent No. 3118915.
The following technique is discussed in Japanese Patent Application Laid-Open No. 2007-257087. A flesh color distribution model is created from flesh color data of a wide variety of people. Thereafter, presence of a human face is identified from an input image, and a flesh color distribution model is created from data of flesh color pixels in a region of the identified face. A modified flesh color distribution model is created by weighing and adding up these flesh color distribution models. Flesh color likelihood corresponding to each of the pixels in the input image data is acquired by using the modified flesh color distribution model. Then, as to whether the color of each pixel data group of the input image data is a flesh color is determined by comparing the flesh color likelihood and a threshold value.
Further, the following technique is discussed in Japanese Patent Application Laid-Open No. 2005-228140. Pieces of color information are each extracted from a background image without an object and a background image with an object. These pieces of color information are compared with each other, and color information that is not included in the background image without an object is registered as color information of the object from among the color information of the background image with an object. Further, detection precision of a color of the object region is improved by adjusting color information of a noise region that is specified by a user from the object region.
Further, according to the technique discussed in Japanese Patent No. 3118915, a color table is created according to a pixel position while a color table to be used is specified at each pixel. Then, a color of each pixel is extracted by using a specified color table.
However, when the techniques described in Japanese Patent Application Laid-Open No. 2007-257087 or Japanese Patent Application Laid-Open No. 2005-228140 is employed, there is a risk that the color of the object region cannot be extracted correctly when a tint varies depending on pixel positions. For example, in an image captured by a camera showing limb darkening, luminance or tint is different in a central portion and an edge portion. Therefore, if the color information is registered only in a vicinity of the central portion of the captured image, the color is more likely to be undetected at the edge portion of the image plane. On the other hand, if the color information is registered at the entire region of the image plane, over-detection of the color increases.
On the other hand, with the technique described in Japanese Patent No. 3118915, a registered color can be extracted regardless of a region in the captured image because a color table is created at each of the pixels in the image. However, it is hard to realize the above-described technique because a huge memory will be necessary to create the color table for each of the pixels.